SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '963e05de8b320b72291e80e873b907198c16fe0db25a7f553be7b9226f407c7a' 
  AND token = '/zgxd5QGrDO4+qnmPYqJgxm9M/hGqnbHfa/QwxK2QKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}